Packing machine for folding blanks around article groups fed continuously therethrough

ABSTRACT

Segregated groups of articles are mated with an initially flat blank which is then folded into a U-shaped configuration around the bottom, front and top sides of the group articles. A pocket chain conveyor receives the U-folded case, with its article group, and each pocket includes a rear gate for folding a trailing bottom flap upwardly against the rear side of the article group. An overhead flight bar then folds a trailing top flap, or rear panel of the blank, downwardly so that a second rear gate on the pocket chain can hold both top and bottom rear flaps in place prior to folding the laterally opposed side flaps inwardly against the sides of the case. The trailing top flap, or rear panel, has side flaps which must be folded forwardly, and this is done by spaced elements on the flight bar. These elements engage the rear panel side flaps adjacent their respective fold lines so that the rear panel is not only folded downwardly as described, but so that as the rear panel abuts the rear of the case, further forward movement of these elements creases the side flaps at their respective fold lines to fold them forwardly. The remaining side flaps are folded in a conventional manner by fixed ploughs or the like.

United States Patent De Barge [54] PACKING MACHINE FOR FOLDING BLANKS AROUND ARTICLE GROUPS FED CONTINUOUSLY THERETHROUGH [72] Inventor: Raymond R. De Barge, Cromwell,

Conn.

[73] Assignee: Fanhart Corporation, Bloomfield,

Conn.

[22] F iled: June 22, 1970 [211 Appl. No.: 48,408

[$21 US. Cl ..53/209, 53/374 [Sl] Int. Cl. ..B65b 7/20, 8455b 49/l4 [58] Field ofSearch ..53/29, l83, I86, 207, 209,

Primary Examiner-Theron E. Condon Assistant Examiner-Eugene F. Desmond AnomeyMcCormick, Paulding & Huber [is] 3,681,893 1 Aug. 8, 1972 ABSTRACT Segregated groups of articles are mated with an initially flat blank which is then folded into a U-shaped configuration around the bottom, front and top sides of the group articles. A pocket chain conveyor receives the U-folded case, with its article group, and each pocket includes a rear gate for folding a trailing bottom flap upwardly against the rear side of the article group. An overhead flight bar then folds a trailing top flap, or rear panel of the blank, downwardly so that a second rear gate on the pocket chain can hold both top and bottom rear flaps in place prior to folding the laterally opposed side flaps inwardly against the sides of the case. The trailing top flap, or rear panel, has side flaps which must be folded forwardly, and this is done by spaced elements on the flight bar. These elements engage the rear panel side flaps adjacent their respective fold lines so that the rear panel is not only folded downwardly as described, but so that m the rear panel abuts the rear of the case, further forward movement of these elements creases the side flaps at their respective fold lines to fold them forwardly. The remaining side flaps are folded in a conventional manner by fixed ploughs or the like.

5 Claims, 15 Drawing Figures PATENTEUA B 9 I97? SHEET 10F 4 .VVENTOR. RAYMOND R. De BARGE ATTORNEYS PATENTEBA B M2 3.681.893 SHEET 30$ 4 PACKING MACHINE FOR FOLDING BLANKS AROUND ARTICLE GROUPS FED CONTINUOUSLY 'I'l-[ERETHROUGH BACKGROUND OF THE INVENTION This invention relates to machines for forming packing cases around groups or slugs of articles fed continuously in one direction, and deals more particularly with an improvement to a machine of the type shown in U.S. Pat. No. 3,513,630 issued May 26, 1970 and assigned to the assignee herein.

In the machine shown and described in the abovementioned patent, segregated groups of articles are fed to the machine first by a flight bar conveyor and then by a pocket chain conveyor. The invention described herein relates to the upstream end of the pocket chain conveyor. A brief resume of the construction shown in the above-mentioned patent will be given by way of background.

A stack of flat packing case blanks is stored in a magazine alongside the primary flight bar conveyor, and fingers withdraw the lowermost blank in the stack so that a pair of short belt conveyors can move the blank to a preliminary position spaced below a deadplate across which the article groups are advanced by the primary flight bar conveyor. Counter rotating blank lifting fingers raise the blank against the underside of the deadplate, so that depending fingers on the primary flight bar advance the blank together with an as sociated article group off the downstream edge of the deadplate. A rotary device downstream of the deadplate creases the blank at the lower front comer of the article group, and a vertically reciprocable roller creases the blank at the upper front corner thereof to form the blank into a U-shaped configuration around the article group. As so configured, the pocket chain conveyor receives the U-folded case, with its article group, and each pocket on the pocket chain conveyor includes a first rear gate for folding the trailing bottom flap upwardly against the rear side of the article group. Finally, and still with reference to the construction shown in the above-identified United States Patent, a secondary overhead flight bar then folds the trailing top flap, or rear panel downwardly, so that a second gate on the pocket chain conveyor can hold both the top and bottom rear flaps in place while the laterally opposed sides of the case are folded in a conventional manner. More particularly, and as shown in FIG. 1 of the above-mentioned patent, pivotally mounted vanes 130, 130 are provided for folding the rear panel associated side flaps since these flaps must be folded forwardly at a speed greater than that of the articles and carton being fed by the pocket chain conveyor. Finally, fixed plough means 136 are provided for folding the remaining side flaps of the case.

In order to eliminate the need for the critical timing of the motion of the pivotally mounted vanes mentioned in the preceding paragraph, these vanes are replaced in the present disclosure by elements provided on the overhead flight bar which folds the rear panel downwardly. Thus, the rear panel side flaps are folded forwardly and positively in timed relationship with folding of the rear panel itself without resorting to a complicated mechanism of the type shown and described in the above-identified patent.

SUMMARY OF INVENTION ln an apparatus of the type described in the abovementioned US. Pat. No. 3,5 [3,630, and including means for forming a carton blank around a continuously advancing group of articles, said blank having bottom, front, top and rear panels each of which panels carries left and right-hand associated side flaps, improved rneans is provided for folding certain of these side flaps. The above-mentioned apparatus is adapted to fold a blank into a U-shaped configuration enclosing the bottom, front and top of a group of articles, and the U-shaped case with the articles is provided in a pocket chain conveyor which includes a front stop against which the U-shaped case can abut, and has a rear gate which includes a first gate member adapted to fold a trailing bottom flap, or manufacturers tab, upwardly against the rear side of the group of articles. A rear panel folding flight bar is adapted to fold the rear panel, or trailing top flap, downwardly against the rear of the case, and in accordance with the present invention, said flight bar is not only movable forwardly and downwardly behind the U-shaped blank to fold the rear panel against the rear row of articles in the group and against the trailing bottom flap, but said flight bar is also provided with left and right-hand laterally spaced side flap tucking elements which project forwardly and downwardly therefrom for engaging the left and righthand side flaps of the case adjacent their respective fold lines. The spacing between these elements is such that they serve to first fold the rear panel downwardly, and to subsequently fold the left and right-hand side flaps associated with the rear panel forwardly prior to upward movement of the flight bar away from the packing case. A second gate member on the pocket chain conveyor holds the rear panel in the folded condition m in the above-identified patent.

Thus, the general object of the present invention is to provide a machine of the type shown in the aboveidentified United States patent which incorporates a novel mechanism for folding certain of the laterally extending side flaps of the packing case, particularly the side flaps associated with the rear panel. These flaps are required to be folded forwardly instead of simply being folded either rearwardly or upwardly or downwardly as is true of the remaining side flaps in a packing case of this type and heretofore, mechanism has been required capable of somemore complex motion for accomplishing this function.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing the path of movement of the rear panel folding flight bar for use in folding the rear panel downwardly and forwardly against the rear side of a U-shaped carton provided in conjunction with a slug of articles being handled by a machine of the type shown in the above-identified US. Pat. No. 3,513,630.

FIG. 1A is a fragmentary sectional view of one end of the rear flap folding flight bar.

FIG. 2 is a perspective view of the flight bar provided on the flight bar conveyor system shown in FIG. 1 showing the relationship of the flight bar at the moment when its laterally spaced flap tucking elements engage the rear panel of a generally U-shaped carton blank.

FIG. 3 is a view similar to FIG. 2, but taken at a slightly later instant of time after the rear panel has been folded through substantially 90.

FIG. 4 is a perspective view similar to FIGS. 2 and 3 showing the flight bar as it rotates in traveling around the lowermost sprockets associated with the flight bar conveyor system shown in FIG. 1, which rotation causes forward movement of the flap tucking elements whereby the rear panel side flaps are folded forwardly in relationship to the forwardly moving packing case.

FIG. 5 is a perspective view showing the initially flat carton blank in association with the articles about which the carton blank is adapted to be folded into a U- shaped configuration as shown in FIG. 2.

FIGS. 6, 7, 8, 9, l and 11 are elevational views showing in schematic fashion the orientation of the flight bar, and of its associated flap tucking elements, in relationship to the carton as the carton is being conveyed from left to right in these views by a pocket chain conveyor indicated schematically by the broken lines.

FIGS. 70 and 100 show the construction of the pocket chain and the mechanism for operating the first and second rear gate members which serve to fold the manufacturers flap prior to downward movement of the rear panel of the packing case. These views are exploded more detailed versions of the above-mentioned in FIGS. 7 and 10, being taken at substantially the same instant of time, respectively.

FIG. 12 shows the folded case as it would appear after being acted upon by the rear panel folding flight bar and its associated flap tucking elements.

DETAILED DESCRIPTION As shown and described in the above-identified US. Pat. No. 3,513,630, segregated groups of slugs of articles are provided on a generally flat carton blank, being conveyed through the machine by a single flight bar having depending fingers for engaging the blank, and having a laterally extending portion for advancing the articles simultaneously therewith. As described in detail in this patent, means is provided for feeding the blanks to this position, and for folding the blank into a generally U-shaped configuration around the forward end portion of each slug of articles as the blank and slug are fed in a downstream direction. As shown in FIG. herein, the initially flat blank has a bottom panel B, connected to a front panel F along a prescored fold line. The front panel F is similarly connected to a top panel T, which top panel is in turn connected to a rear panel R. Each of these panels B, F, T and R includes left and right-hand side flaps l0 and 12 along the marginal side edges of each as indicated by the reference numerals B and 128, etc. Finally, a trailing flap 14 is provided on the bottom panel B, and this flap is sometimes referred to as the manufacturer's tab, or the trailing bottom flap.

The mechanism for folding initially flap blanks into the U-shaped configuration shown in FIG. 2 need not be described in detail herein, and the reader is referred to the above-identified patent for a detailed description of a typical apparatus for accomplishing this purpose. As mentioned above, a primary flight bar conveyor system is adapted to feed the slug of articles together with its associated blank through the first half of the above-identified machine, and as shown schematically in FIGS. 6 through 12 inclusively, the pocket chain conveyor is adapted to feed the U-shaped case of FIG. 2 through the second half of such a machine. These conveyors are, of course, timed with respect to one another, and the individual pockets on the pocket chain conveyor are adapted to receive cartons folded into the configuration of FIG. 2, a stop 92 being provided on the pocket chain for engaging the front end of each case as shown in FIGS. 70, 10a and 12. The pocket chain conveyor includes rests 94, 94 for receiving the bottom of the case and a rear gate is provided on the pocket chain 90 for folding the trailing bottom flap or manufacturers flap upwardly from the position shown in FIG. 2 through the positions shown in FIGS. 6 through 8 inclusively. An arcuate gate 96 moves in the manner suggested in these views as the pocket chain moves over a sprocket (not shown) in the direction indicated by the arrows associated with the pocket chain conveyor 90. This arcuate, or first gate 96 comprises the rear side of this particular pocket. FIG. 6 shows this gate 96 prior to engagement with the trailing bottom flap l4 and FIGS. 7 and 7a show the gate 96 after it has moved upwardly around the sprocket so as to partially fold the trailing bottom flap l4 upwardly and forwardly as shown. As best shown in FIGS. 7a, 10a and 12, this gate 96 comprises an L-shaped member having a flap engaging portion of arcuate shape which extends upwardly beyond the chain 90, and which has a rearwardly extending leg portion 97 pivotally connected to a point on the chain defined by pivot pin 99.

The first gate 96 is held in the raised position shown in FIG. 7a as the pocket chain moves through this particular phase of operation of the machine by a cam follower 100, which cam follower rides in a slot 98 provided in the fixed frame of the machine. The cam follower 100 is carried on one arm 102 of a bell crank, which bell crank is pivotally supported on a second pivot pin 103 on the pocket chain 90. The bell crank has its other arm 104 provided with a slot 106 for receiving a pin 108 provided for this purpose on the first gate 96. Thus, as long as the roller 100 rides in the slot 98, the first gate 96 is maintained in its raised position and thereby holds the trailing bottom fiap 98 in the position shown in FIGS. 7, 7a and 8.

The rear panel R trails the partially enclosed slug of articles on the pocket chain conveyor as suggested in FIGS. 2 and 6, and a rear panel folding flight bar 112 is provided between laterally opposed flight bar conveyor chains 114, 114, only one of which is shown in FIG. 1. Thus, the flight bar 112 moves downwardly between the fixed guides I16, 116. Movement of this rear panel folding flight bar 112 is timed and coordinated with respect to movement of the pocket chain conveyor and particularly of the pockets in which the slug of articles with its U-folded blank is received, through conventional means as described for example in the abovementioned patent. More particularly, the flight bar 112 is so timed with respect to the pocket chain conveyor 90 that it folds the rear panel R downwardly behind the manufacturer's flap 14 which has been folded by the gate 96 in the manner just described.

The flight bar 112 has end portions which are con nected to the chains 114 by U-shaped members 115, 115 and the chains are confined by fixed guides 116,

116 as best shown in FIG. 1A. As will be apparent froms FIGS. 2 and 3, the intermediate portion of the flight bar 112 does not engage the rear panel R during the major portion of its travel in the manner described above with reference to the above-identified patent. It is an important feature of the present invention that the flight bar 112 is provided with rear panel side flap tucking elements 118, 118 for engaging the rear panel R just outboard of the fold lines associated with the left and right-hand side flaps R and 12R respectively. As a result of engagement in the area adjacent these fold lines, these left and right-hand side flaps do not themselves fold about this fold line, but rather the rear panel R folds about its associated fold line between the rear panel R and the top panel T as a result of the larger moment arm associated with the latter fold line. As suggested in FIGS. 3 and 4, only when the side flap tucking elements 1 18, 118 reach a position intermediate FIGS. 8 and 9, that is when the rear panel R engages the rear side of the case, will the left and right hand side flaps 10R and 12R crease about their respective fold lines resulting in forward folding or tucking movement of these side flaps in the manner shown.

A second rear gate 120 associated with the pocket chain conveyor is adapted to hold the rear panel R in position adjacent the rear side of the case and against the upwardly folded previously positioned trailing bottom flap or manufacturers tab. This second gate 120 remains in position long enough on the pocket chain conveyor to permit adhesive applied thereto at an upstream station in the machine to set. The second gate 120 is hingedly connected to the pocket chain conveyor 90 at the pivot pin 103 and comprises an extension of the bell crank arm 104 as best shown in FIGS. 7a, 10a and 12. Thus, as the roller 100 rides upwardly in the inclined slot segment 98c, it will be apparent that the bell crank pivots in a clockwise direction causing the arm 104 and its extension, namely the second gate 120, to pivot clockwise in the direction of the arrow 122 so as to assume the position shown in FIG. 12. At the same time, the first gate 96 is pivoted downwardly about its axis of rotation defined by the pivot pin 99, with the result that these gates 96 and 120 operate in timed relationship with one another to not only fold the trailing bottom flap of the packing case, but to also hold the rear panel in position after it has been folded in the manner just described as a result of the overhead flight bar 112 and its associated side flap tucking elements 118, 118.

As the partially folded case is moved through the machine by the pocket chain conveyor 90, the various left and right-hand side flaps associated with the bottom front and top panels are sequentially folded inwardly against the sides of the case in the manner suggested in FIGS. 2, 3 and 4. More particularly, once control of the U-folded case has been positively obtained by reason of a forward stop 92 and one of the rear gates 96 or 120, a fixed plough (not shown) can fold the left and right-hand bottom side flaps upwardly to the position shown in FIG. 2. A fixed plough (not shown) can also fold the left and right-hand front side flaps 10F and 12F rearwardly to the position shown. The side flaps, 10R and 12R, associated with the rear panel R are folded in the manner just described by the flap tucking elements 118, 118 on the rear flap folding flight bar 1 12.

The semi-folded case or blank is then conveyed through the remainder of the machine by the pocket chain conveyor 90, each case being held between the forward stop 92 and the second gate at the rear of the case so that the top lefi and right-hand side flaps 101' and 12T can be folded downwardly against the sides of the case by still another fixed plough (not shown). The completely folded case can then be removed from the pocket chain conveyor by conventional means.

By way of summary, a slug of articles together with a generally U-shaped carton blank is provided at the upstream end of a pocket chain conveyor having a front stop 92 against which the package can abut, and having a rear pocket defining element in the form of a first gate 96 which is adapted to move through the successive positions shown in FIGS. 6, 7 and 8 to fold the trailing bottom flap or manufacturers tab upwardly against the rear side of the slug of articles in a conventional manner. The left and right-hand side flaps 10B and 12B associated with the bottom panel B are adapted to be folded upwardly against the sides of the slug of articles by fixed ploughs (not shown) to the position shown in FIG. 2. Subsequently, the left and right-hand side flaps 10F and 12F associated with the front panel F of the U-shaped blank are adapted to be folded rearwardly by fixed ploughs (not shown) to the position shown in FIG. 2. These side flaps associated with the bottom and front panels of the blank may be folded either before or afier folding of the trailing bottom flap by the arcuate rear gate 96 of the pocket chain conveyor.

The rear panel R is folded downwardly and forwardly at the same time that the slug of articles is conveyed by the pocket chain conveyor by an overhead flight bar 112, and more particularly through the action of its associated depending flap engaging elements 118, 118. Although these elements engage the left and right-hand side flaps 10R and 12R associated with the rear panel R, they do not fold the side flaps 10R and 12R immediately along their associated fold lines, but rather fold the rear panel R about its associated fold line as shown in FIGS. 2, 3 and 4. As shown in detail in FIG. 9, once the said flight bar reaches the lower limit of its travel, and passes around the sprocket 119, the flap tucking elements 118, 118 rotate in the counterclockwise direction to fold the left and right-hand rear side flaps 10R and 12R forwardly around the slug of articles even as the articles and the semi-folded case are conveyed along by the pocket chain conveyor 90. In order to retain positive control of the case and its associated articles on the pocket chain conveyor, a second gate 120 is moved upwardly behind the case even as the first gate 96 is retracted, and as the flight bar 112 moves upwardly in the direction of the arrows 121 in FIGS. 10 and 11. This second gate 120 serves to hold the rear panel R against the manufactuers tab 14 which has preferably been preglued so that the adhesive will set as the case is conveyed along by the pocket chain conveyor 90. Finally, and as shown in FIG. 12, the left and right-hand side flaps 10T and 12T associated with the top panel T are folded downwardly against the sides of the case by a fixed plough (not shown).

Iclaim:

1. In an apparatus for forming a carton blank around a continuously advancing group of articles, wherein the blank has bottom, front, top and rear panels each of which carries left and right-hand associated side flaps, and said carton blank further including a trailing bottom flap carried by said bottom panel, said apparatus having means for folding the blank into a U-shaped configuration enclosing the bottom front and top of said group of articles, and said apparatus including a pocket chain conveyor for advancing the U-shaped carton together with an associated group of articles in a downstream direction, the improvement comprising a front stop in said pocket chain conveyor for receiving the front panel of said U-shaped carton, a first gate on said pocket chain conveyor for folding said trailing bottom flap against the rear row of articles in said group, a rear panel folding flight bar mounted above the path of movement of said U-shaped blank in said pocket chain conveyor, said flight bar being movable forwardly and downwardly behind the U-shaped blank to fold the rear panel against the rear row of articles in said group, left and right-hand laterally spaced side flap tucking elements carried by said flight bar and projecting forwardly therefrom for engaging the left and right-hand side flaps respectively on said rear panel to fold these forwardly against the sides of the group of articles and said flap tucking elements engaging said side flaps in downwardly spaced relationship to the horizontal laterally extending fold line associated with said rear panel to fold said panel prior to folding said side flaps.

2. The combination defined in claim 1 wherein said flight bar moves downwardly and forwardly to fold said rear panel, and wherein said flight bar moves upwardly once said rear panel is so folded, said side flap tucking elements being mounted to said flight bar so that they project downwardly from it during downward movement thereof and are rotated through a slightly longer arcuate path as said flight bar moves toward its upward direction to fold said side flaps inwardly as a result of the momentary increase in tangential speed of said flight bar mounted elements.

3. In an apparatus for folding a carton blank around a group of articles being continuously fed in one direction the improvement comprising means for folding a trailing rear panel of the carton blank and then folding its laterally opposed side flaps as the partially folded carton is being so fed, said means including an overhead flight bar which moves downwardly and forwardly behind the partially folded carton at a speed slightly greater than that of said carton, side flap tucking elements carried by said flight bar in depending relationship thereto for engaging the side flaps on said rear panel adjacent their associated prescored fold lines and said flap tucking elements engaging said side flaps in downwardly spaced relationship to the horizontal laterally extending fold line associated with said rear panel to fold said panel prior to folding said side flaps.

4. The combination defined in claim 3 wherein said flap tucking elements are rigidly secured to said flight bar, and wherein said flight bar moves upwardly following the folding of said rear panel causing said tucking elements to move forwardly and upwardly at a tangential speed greater than that of said flight bar to fold said side flaps inwardly against the sides of the partially lira h a p paratus for fonning a carton blank around a continuously advancing group of articles, wherein the blank has bottom, front, top and rear panels each of which carries left and right-hand associated side flaps, and said carton blank further including a trailing bottom flap carried by said bottom panel, said apparatus having means for folding the blank into a U-shaped configuration enclosing the bottom front and top of said group of articles, and said apparatus including a pocket chain conveyor for advancing the U-shaped carton together with an associated group of articles in a downstream direction, the improvement comprising a front stop on said pocket chain conveyor for receiving the front panel of said U-shaped carton, a first gate on said pocket chain conveyor for folding said trailing bottom flap against the rear row of articles in said group, a rear panel folding flight bar mounted above the path of movement of said U-shaped blank in said pocket chain conveyor, said flight bar being movable forwardly and downwardly behind the U-shaped blank to fold the rear panel against the rear row of articles in said group, left and right-hand laterally spaced side flap tucking elements carried by said flight bar and projecting forwardly therefrom for engaging the left and right-hand side flaps respectively on said rear panel to fold these forwardly against the sides of the group of articles, said flight bar moves upwardly once said rear panel is so folded, said side flap tucking elements being mounted to said flight bar so that they project downwardly from it during downward movement thereof and are rotated through a slightly longer arcuate path as said flight bar moves toward its upward direction to fold said side flaps inwardly as a result of the momentary increase in tangential speed of said flight bar mounted elements.

* h i l 

1. In an apparatus for forming a carton blank around a continuously advancing group of articles, wherein the blank has bottom, front, top and rear panels each of which carries left and right-hand associated side flaps, and said carton blank further including a trailing bottom flap carried by said bottom panel, said apparatus having means for folding the blank into a U-shaped configuration enclosing the bottom front and top of said group of articles, and said apparatus including a pocket chain conveyor for advancing the U-shaped carton together with an associated group of articles in a downstream direction, the improvement comprising a front stop in said pocket chain conveyor for receiving the front panel of said U-shaped carton, a first gate on said pocket chain conveyor for folding said trailing bottom flap against the rear row of articles in said group, a rear panel folding flight bar mounted above the path of movement of said Ushaped blank in said pocket chain conveyor, said flight bar being movable forwardly and downwardly behind the U-shaped blank to fold the rear panel against the rear row of articles in said group, left and right-hand laterally spaced side flap tucking elements carried by said flight bar and projecting forwardly therefrom for engaging the left and right-hand side flaps respectively on said rear panel to fold these forwardly against the sides of the group of articles and said flap tucking elements engaging said side flaps in downwardly spaced relationship to the horizontal laterally extending fold line associated with said rear panel to fold said panel prior to folding said side flaps.
 2. The combination defined in claim 1 wherein said flight bar moves downwardly and forwardly to fold said rear panel, and wherein said flight bar moves upwardly once said rear panel is so folded, said side flap tucking elements being mounted to said flight bar so that they project downwardly from it during downward movement thereof and are rOtated through a slightly longer arcuate path as said flight bar moves toward its upward direction to fold said side flaps inwardly as a result of the momentary increase in tangential speed of said flight bar mounted elements.
 3. In an apparatus for folding a carton blank around a group of articles being continuously fed in one direction the improvement comprising means for folding a trailing rear panel of the carton blank and then folding its laterally opposed side flaps as the partially folded carton is being so fed, said means including an overhead flight bar which moves downwardly and forwardly behind the partially folded carton at a speed slightly greater than that of said carton, side flap tucking elements carried by said flight bar in depending relationship thereto for engaging the side flaps on said rear panel adjacent their associated prescored fold lines and said flap tucking elements engaging said side flaps in downwardly spaced relationship to the horizontal laterally extending fold line associated with said rear panel to fold said panel prior to folding said side flaps.
 4. The combination defined in claim 3 wherein said flap tucking elements are rigidly secured to said flight bar, and wherein said flight bar moves upwardly following the folding of said rear panel causing said tucking elements to move forwardly and upwardly at a tangential speed greater than that of said flight bar to fold said side flaps inwardly against the sides of the partially folded carton.
 5. In an apparatus for forming a carton blank around a continuously advancing group of articles, wherein the blank has bottom, front, top and rear panels each of which carries left and right-hand associated side flaps, and said carton blank further including a trailing bottom flap carried by said bottom panel, said apparatus having means for folding the blank into a U-shaped configuration enclosing the bottom front and top of said group of articles, and said apparatus including a pocket chain conveyor for advancing the U-shaped carton together with an associated group of articles in a downstream direction, the improvement comprising a front stop on said pocket chain conveyor for receiving the front panel of said U-shaped carton, a first gate on said pocket chain conveyor for folding said trailing bottom flap against the rear row of articles in said group, a rear panel folding flight bar mounted above the path of movement of said U-shaped blank in said pocket chain conveyor, said flight bar being movable forwardly and downwardly behind the U-shaped blank to fold the rear panel against the rear row of articles in said group, left and right-hand laterally spaced side flap tucking elements carried by said flight bar and projecting forwardly therefrom for engaging the left and right-hand side flaps respectively on said rear panel to fold these forwardly against the sides of the group of articles, said flight bar moves upwardly once said rear panel is so folded, said side flap tucking elements being mounted to said flight bar so that they project downwardly from it during downward movement thereof and are rotated through a slightly longer arcuate path as said flight bar moves toward its upward direction to fold said side flaps inwardly as a result of the momentary increase in tangential speed of said flight bar mounted elements. 